1 October 2017 Macroinvertebrate Functional Organisation Along the Longitudinal Gradient of an Austral Temperate River
Sydney Moyo, Nicole B Richoux
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The Kowie River, a relatively pristine system in South Africa, was sampled on four occasions over one year to determine if relative abundances of functional feeding groups (FFGs) of invertebrates changed along the longitudinal gradient, and if these changes matched predictions of the river continuum concept (RCC). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50–83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was <10% at all sites and times). The changes in relative abundances of the different FFGs did not always follow the predictions of the RCC, as there were no correlations of community structure with river width or canopy cover in some seasons; however, some predictions of the RCC were supported, as a dominance of filterers (with relatively small contributions from shredders and grazers) and a consistent presence of predators were recorded. The FFG abundances were correlated with water velocity and total dissolved solids. Broadly, shifts in relative abundances of FFGs along the river continuum could not be explained by physical attributes alone, and were probably influenced by the availability of food and the chemistry of the river. Our findings highlight the need for theoretical and field studies across a broad array of African systems to refine the applicability of the RCC and FFG classifications to further develop models of ecosystem function.

© Zoological Society of Southern Africa
Sydney Moyo and Nicole B Richoux "Macroinvertebrate Functional Organisation Along the Longitudinal Gradient of an Austral Temperate River," African Zoology 52(3), 125-136, (1 October 2017). https://doi.org/10.1080/15627020.2017.1354721
Received: 8 February 2017; Accepted: 19 July 2017; Published: 1 October 2017
functional feeding groups
Kowie River
river continuum concept
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